private void delete_btnMouseClicked(java.awt.event.MouseEvent evt) {
    // TODO add your handling code here:
    int delete = JOptionPane.showConfirmDialog(this, "Are you sure you want to delete nthis person from your contacts?", "Delete Contact", JOptionPane.YES_NO_CANCEL_OPTION);
    int indexno = jList1.getSelectedIndex();
    if (delete == 1) {
        jList1.setModel(dlm);
        dlm.removeElementAt(indexno);
        try {
            String update = "delete from contacts where user = '" + Login.jTextField1.getText() + "' and contacts = '" + jList1.getSelectedValue() + "';";
            Login.connectionUpdate(update);
        }
        catch (Exception e){
            e.printStackTrace();
        }
    }
}

public static void connectionUpdate(String update) throws ClassNotFoundException, SQLException {
    Class.forName("java.sql.DriverManager");
    Connection con = (Connection) DriverManager.getConnection("jdbc:mysql://localhost:3306/chatroom", "root", "ForbiddenVoices!");
    Statement stmt = (Statement) con.createStatement();
    String check = update;
    stmt.executeUpdate(check);
}